Electronic circuit package

ABSTRACT

Disclosed herein is an electronic circuit package includes a substrate having a power supply pattern, a first electronic component mounted on a first region of a front surface of the substrate, a mold resin that covers the front surface of the substrate so as to embed the first electronic component therein and has a concave portion above the first region, a magnetic film selectively provided in the concave portion, and a first metal film that is connected to the power supply pattern and covers the mold resin.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an electronic circuit package and, moreparticularly, to an electronic circuit package provided with a compositeshielding function having both an electromagnetic shielding function anda magnetic shielding function.

Description of Related Art

In recent years, an electronic device such as a smartphone is equippedwith a high-performance radio communication circuit and ahigh-performance digital chip, and an operating frequency of asemiconductor IC used therein tends to increase. Further, adoption of anSIP (System-In Package) having a 2.5D or 3D structure, in which aplurality of semiconductor ICs are connected by a shortest wiring, isaccelerated, and modularization of a power supply system is expected toaccelerate. Further, an electronic circuit module having a large numberof modulated electronic components (collective term of components, suchas passive components (an inductor, a capacitor, a resistor, a filter,etc.), active components (a transistor, a diode, etc.), integratedcircuit components (an semiconductor IC, etc.) and other componentsrequired for electronic circuit configuration) is expected to becomemore and more popular, and an electronic circuit package which is acollective term for the above SIP, electronic circuit module, and thelike tends to be mounted in high density along with sophistication,miniaturization, and thinning of an electronic device such as asmartphone. However, this tendency poses a problem of malfunction andradio disturbance due to noise. The problem of malfunction and radiodisturbance is difficult to be solved by conventional noisecountermeasure techniques. Thus, recently, self-shielding of theelectronic circuit package has become accelerated, and anelectromagnetic shielding using a conductive paste or a plating orsputtering method has been proposed and put into practical use, andhigher shielding characteristics are required in the future.

In order to realize the higher shielding characteristics, a compositeshielding structure is proposed in recent years. The composite shieldingstructure has both an electromagnetic shielding function and a magneticshielding function. In order to realize the composite shieldingstructure, it is necessary to form, in an electronic circuit package, anelectromagnetic shielding by a conductive film (metal film) and amagnetic shielding by a magnetic film.

For example, the semiconductor package described in U.S. PatentPublication No. 2011/0304015 has a configuration in which a shield case(shield can) obtained by laminating a magnetic layer and a metal layeris bonded to a mold resin by adhesive. The semiconductor packagedescribed in U.S. Patent Publication No. 2013/0307128 has aconfiguration in which the surface of a mold resin is covered with ametal shield and a concave portion is formed in the mold resin so as toexpose the upper surface of a semiconductor chip therethrough and thenfilled with a metal material or the like.

However, the configuration described in U.S. Patent Publication No.2011/0304015 where an adhesive is used to bond the shield case is notonly disadvantageous in terms of height reduction, but also makes itharder for the metal film to be connected to a ground pattern on asubstrate. Further, the configuration described in U.S. PatentPublication No. 2013/0307128 where the concave portion formed in themold resin is filled with a metal material or the like can enhance heatradiation performance; however, since it does not have a compositeshield structure, shielding characteristics, especially in a lowfrequency region, are insufficient.

SUMMARY

The object of the present invention is therefore to provide anelectronic circuit package capable of achieving both high compositeshielding effect and height reduction.

An electronic circuit package according to the present inventionincludes a substrate having a power supply pattern, a first electroniccomponent mounted in a first region on the front surface of thesubstrate, a mold resin that covers the front surface of the substrateso as to embed the first electronic component therein and has a concaveportion above the first region, a magnetic film selectively provided inthe concave portion, and a first metal film that is connected to thepower supply pattern and covers the mold resin.

According to the present invention, a laminated film of the magneticfilm and metal film is formed above the first region, so that highcomposite shielding characteristics with respect to the first electroniccomponent can be obtained. That is, in an electronic circuit package,not all the electronic components mounted on the substrate are noisesources, but only some specific electronic components may be noisesources. Further, it is often the case that not all the electroniccomponents mounted on the substrate are insusceptible to external noise.In the present invention, the laminated film is selectively providedabove the electronic component for which noise countermeasures areparticularly required, whereby it is possible to suppress peak noisegenerated around the electronic component and to prevent malfunction ofthe electronic component susceptible to external noise. Further, themagnetic film is selectively provided in the concave portion of the moldresin, enabling height reduction to be achieved. In addition, manymagnetic materials have a higher thermal conductivity than the moldresin, so that radiation performance can be enhanced.

In the present invention, the first metal film may also cover themagnetic film. Alternatively, the first metal film may be positionedbetween the mold resin and the magnetic film in the concave portion.According to the former, noise radiated from the first electroniccomponent can effectively be shielded and, according to the latter,external noise to be incident on the first electronic component caneffectively be shielded. Further, by providing a second metal film thatcovers the magnetic film, the above both effects can be obtained.

The electronic circuit package according to the present inventionfurther preferably includes a second electronic component mounted in asecond region on the front surface of the substrate, and the firstelectronic component is preferably lower in height than the secondelectronic component. With this configuration, the concave portion isformed by exploiting the difference in height between the first andsecond electronic components, thus preventing increase in the height ofthe entire electronic circuit package that may be caused due to theformation of the concave portion.

In the present invention, the upper surface of the first electroniccomponent is preferably exposed to the concave portion, and hence, theupper surface of the first electronic component preferably contacts themagnetic film or the first metal film. With this configuration, thethickness of the magnetic film can be made larger, thereby making itpossible to enhance magnetic shielding characteristics. In addition,since the upper surface of the first electronic component contacts themagnetic film or the first metal film, high radiation performance can beobtained.

In the present invention, the planar size of the concave portion ispreferably larger than that of the first electronic component, andhence, the concave portion preferably overlaps the entire firstelectronic component in a plan view. With this configuration, the entirefirst electronic component can be covered with a laminated body of themagnetic film and metal film.

In the present invention, the magnetic film preferably has a portionthat covers a part of the side surface of the mold resin. With thisconfiguration, noise radiated from the first electronic component to theside direction and noise to be incident on the first electroniccomponent from the side direction can be attenuated.

In the present invention, the power supply pattern is preferably exposedto the front surface or the side surface of the substrate, and the firstmetal film preferably contacts the power supply pattern exposed to thefront surface or the side surface of the substrate. With thisconfiguration, the metal film can be easily and reliably connected tothe power supply pattern.

In the present invention, the magnetic film may be a film formed of acomposite magnetic material in which magnetic fillers are dispersed in athermosetting resin material, or a thin film, a foil or a bulk sheetformed of a soft magnetic material or a ferrite. When the film formed ofa composite magnetic material is used, the magnetic filler is preferablyformed of a ferrite or a soft magnetic metal, and a surface of thefiller is preferably insulation-coated.

Preferably, in the present invention, the metal film is mainly composedof at least one metal selected from a group consisting of Au, Ag, Cu,and Al, and more preferably, the surface of the metal film is coveredwith an antioxidant film.

As described above, according to the present invention, it is possibleto realize both high composite shielding effect and reduction in height.

BRIEF DESCRIPTION OF THE DRAWINGS

The above features and advantages of the present invention will be moreapparent from the following description of certain preferred embodimentstaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a cross-sectional view illustrating a configuration of anelectronic circuit package according to a first embodiment of thepresent invention;

FIGS. 2 to 5 are process views for explaining a manufacturing method forthe electronic circuit package shown in FIG. 1;

FIG. 6 is a process view for explaining a first method for forming aconcave portion in a mold resin;

FIGS. 7 and 8 are process views for explaining a second method forforming a concave portion in a mold resin;

FIGS. 9 to 11 are process views for explaining a third method forforming a concave portion in a mold resin;

FIG. 12 is a cross-sectional view illustrating a configuration of anelectronic circuit package according to a first modification of thefirst embodiment;

FIG. 13 is a cross-sectional view illustrating a configuration of anelectronic circuit package according to a second modification of thefirst embodiment;

FIG. 14 is a planar view illustrating a first layout of a side magneticfilm;

FIG. 15 is a planar view illustrating a second layout of a side magneticfilm;

FIG. 16 is a planar view illustrating a third layout of a side magneticfilm;

FIG. 17 is a planar view illustrating a fourth layout of a side magneticfilm;

FIG. 18 is a cross-sectional view illustrating a configuration of anelectronic circuit package according to a second embodiment of thepresent invention;

FIGS. 19 and 20 are process views for explaining a manufacturing methodfor the electronic circuit package shown in FIG. 18;

FIG. 21 is a cross-sectional view illustrating a configuration of anelectronic circuit package according to a first modification of thesecond embodiment;

FIG. 22 is a cross-sectional view illustrating a configuration of anelectronic circuit package according to a second modification of thesecond embodiment;

FIG. 23 is a cross-sectional view illustrating a configuration of anelectronic circuit package according to a third embodiment of thepresent invention;

FIGS. 24 to 26 are process views for explaining a manufacturing methodfor the electronic circuit package shown in FIG. 23;

FIG. 27 is a cross-sectional view illustrating a configuration of anelectronic circuit package according to a first modification of thethird embodiment; and

FIG. 28 is a cross-sectional view illustrating a configuration of anelectronic circuit package according to a second modification of thethird embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will be explained belowin detail with reference to the accompanying drawings.

First Embodiment

FIG. 1 is a cross-sectional view illustrating a configuration of anelectronic circuit package 11A according to the first embodiment of thepresent invention.

As illustrated in FIG. 1, the electronic circuit package 11A accordingto the present embodiment includes a substrate 20, a plurality ofelectronic components 31 and 32 mounted on the substrate 20, a moldresin 40 covering a front surface 21 of the substrate 20 so as to embedthe electronic components 31 and 32, a magnetic film 50 formed in aconcave portion 47 of the mold resin 40, and a metal film 60 coveringthe mold resin 40 and the magnetic film.

Although the type of the electronic circuit package 11A according to thepresent embodiment is not especially limited, examples thereof include ahigh-frequency module handling a high-frequency signal, a power supplymodule performing power supply control, an SIP (System-In-Package)having a 2.5D structure or a 3D structure, and a semiconductor packagefor radio communication or digital circuit. Although only two electroniccomponents 31 and 32 are illustrated in FIG. 1, more electroniccomponents are incorporated actually.

The substrate 20 has a double-sided and multilayer wiring structure inwhich a large number of wirings are embedded therein and may be any typeof substrate including: a thermosetting resin based organic substratesuch as an FR-4, an FR-5, a BT, a cyanate ester substrate, a phenolsubstrate, or an imide substrate; a thermoplastic resin based organicsubstrate such as a liquid crystal polymer; an LTCC substrate; an HTCCsubstrate; and a flexible substrate. In the present embodiment, thesubstrate 20 has a four-layer structure including wiring layers formedon the front surface 21 and a back surface 22 and two wiring layersembedded therein. Land patterns 23 are an internal electrode forconnecting to the electronic components 31 and 32. The land patterns 23and each of the electronic components 31 and 32 are electrically andmechanically connected to each other through a respective solder 24 (ora conductive paste). For example, the electronic component 31 is asemiconductor chip such as a controller, and electronic component 32 isa passive component such as a capacitor or a coil. Some electroniccomponents (e.g., thinned semiconductor chip) may be embedded in thesubstrate 20.

The electronic component 31 as a semiconductor chip is mounted in afirst region 21A of the surface 21 of the substrate 20, and theelectronic component 32 as a passive component is mounted in a secondregion 21B of the surface 21 of the substrate 20. The first region 21Aand the second region 21B are different regions in a plan view. In thepresent embodiment, the electronic component 31 mounted in the firstregion 21A is lower in height than the electronic component 32 mountedin the second region 21B. Further, the electronic component 31 easilygenerates noise or is subject to external noise. In the presentembodiment, a composite shield structure is selectively applied to theelectronic component 31.

The land patterns 23 are connected to external terminals 26 formed onthe back surface 22 of the substrate 20 through internal wirings 25formed inside the substrate 20. Upon actual use, the electronic circuitpackage 11A is mounted on an unillustrated mother board, and landpatterns on the mother board and the external terminals 26 of theelectronic circuit package 11A are electrically connected. A materialfor a conductor forming the land patterns 23, internal wirings 25, andexternal terminals 26 may be a metal such as copper, silver, gold,nickel, chrome, aluminum, palladium, indium, or a metal alloy thereof ormay be a conductive material using resin or glass as a binder; however,when the substrate 20 is an organic substrate or a flexible substrate,copper or silver is preferably used in terms of cost and conductivity.The above conductive materials may be formed by using various methodssuch as printing, plating, foil lamination, sputtering, vapordeposition, and inkjet.

Out of the internal wirings 25 illustrated in FIG. 1, internal wirings25G are power supply patterns. The power supply patterns 25G aretypically ground patterns to which a ground potential is to be applied;however, it is not limited to the ground patterns as long as the powersupply patterns 25G are a pattern to which a fixed potential is to beapplied.

The mold resin 40 covers the surface 21 of the substrate 20 so as toembed therein the electronic components 31 and 32. In the presentembodiment, a side surface 42 of the mold resin 40 and a side surface 27of the substrate 20 form the same plane. As a material for the moldresin 40, a material based on a thermosetting material or athermoplastic material and blended with fillers for adjusting a thermalexpansion coefficient can be used.

An upper surface 41 of the mold resin 40 has a concave portion 47 abovethe first region 21A in which the electronic component 31 is mounted.Thus, at the position corresponding to the concave portion 47, thethickness of the mold resin 40 is smaller than that of the otherportion. In particular, the concave portion 47 is not formed above thesecond region 21B in which the electronic component 32 is mounted, sothat the thickness of the mold resin 40 on the first region 21A issmaller than the thickness of the mold resin 40 on the second region21B. In the present embodiment, the planar size of the concave portion47 is larger than the planar size of the electronic component 31,whereby the concave portion 47 overlaps the entire electronic component31 in a plan view. In the present embodiment, the electronic component31 is smaller in height than the electronic component 32, so that it ispossible to form the concave portion 47 having the above configurationwithout increasing the thickness of the entire mold resin 40. The bottomsurface of the concave portion 47 may be disposed at a position higherthan the upper surface of the electronic component 32.

The concave portion 47 formed in the mold resin 40 is filled with amagnetic film 50. In the present embodiment, the magnetic film 50 isselectively formed only in the concave portion 47. That is, the magneticfilm 50 is not formed in other portion, particularly, on the secondregion 21B. Hence, even with the presence of the magnetic film 50, theheight of the entire electronic circuit package 11A is not increased, oris increased but to a minimum. In particular, by making the thickness ofthe magnetic film 50 equal to or less than the depth of the concaveportion 47, the height of the entire electronic circuit package 11A isnot increased at all. To obtain higher shielding effect while achievingheight reduction, the upper surface 51 of the magnetic film 50preferably should be almost flush with the upper surface 41 of the moldresin 40.

Although not limited, the magnetic film 50 preferably directly contactsthe mold resin 40 without intervention of an adhesive. The magnetic film50 is a film formed of a composite magnetic material in which magneticfillers are dispersed in a thermosetting resin material, a thin filmformed of a soft magnetic material or ferrite, or formed of a foil or abulk sheet and functions as a magnetic shield.

When the film formed of a composite magnetic material is selected as themagnetic film 50, an epoxy resin, a phenol resin, a silicone resin, adiallyl phthalate resin, a polyimide resin, an urethane resin, and thelike may be used as the thermosetting resin material, and the magneticfilm 50 can be formed by using a thick-film formation method such as aprinting method, a molding method, a slit nozzle coating method, a spraymethod, a dispensing method, an injection method, a transfer method, acompression molding method, or a lamination method using an uncuredsheet-like resin. Using the thermosetting resin material can increasereliability (heat resistance, insulation performance, impact resistance,falling resistance) required for electronic circuit packages.

As the magnetic filler, a ferrite or a soft magnetic metal is preferablyused, and a soft magnetic metal having a high bulk permeability is morepreferably used. As the ferrite or soft magnetic metal, one or two ormore metals selected from a group consisting of Fe, Ni, Zn, Mn, Co, Cr,Mg, Al, and Si and oxides thereof may be used. Specific examples includea ferrite (Ni—Zn ferrite, Mn—Zn ferrite, Ni—Cu—Zn ferrite, etc.), apermalloy (Fe—Ni alloy), a super permalloy (Fe—Ni—Mo alloy), a sendust(Fe—Si—Al alloy), an Fe—Si alloy, an Fe—Co alloy, an Fe—Cr alloy, anFe—Cr—Si alloy, Fe—Ni—Co alloy, and Fe. The shape of the magnetic filleris not especially limited; however, it may be formed into a sphericalshape for a high filling level, and fillers of a plurality of particlesizes may be blended for a densest filling structure. In order tomaximize a shield effect by a permeability real component and a thermalconversion effect by a loss of a permeability imaginary component, themagnetic filler is more preferably formed by adding flat powder havingan aspect ratio of 5 or more.

Preferably, the surface of the magnetic filler is insulation-coated byan oxide of a metal such as Si, Al, Ti, or Mg, or an organic materialfor enhancing fluidity, adhesion, and insulation performance. Theinsulation coating may be formed by coating a thermosetting material onthe surface of the magnetic filler. Alternatively, an oxide film may beformed as the insulation coating by dehydration reaction of a metalalkoxide, and in this case, formation of a silicon oxide coating film ismost preferable. More preferably, organic functional coupling treatmentis applied to the formed coating film.

The composite magnetic material can be formed in the concave portion 47of the mold resin using a known method such as a printing method, amolding method, a slit nozzle coating method, a spray method, adispensing method, or a lamination method using an uncured sheet-likeresin.

When the thin film formed of a soft magnetic material or a ferrite isselected as the magnetic film 50, one or two or more metals selectedfrom a group consisting of Fe, Ni, Zn, Mn, Co, Cr, Mg, Al, and Si andoxides thereof may be used. In this case, the magnetic film 50 can beformed in the concave portion 47 of the mold resin 40 by using a platingmethod, a spray method, an AD method, and a thermal spraying method, aswell as a thin-film formation method such as a sputtering method or avapor-deposition method. In this case, the material for the magneticfilm 50 may be appropriately selected from a required permeability andfrequency; however, in order to enhance a shield effect on a lowerfrequency side (kHz to 100 MHz), an Fe—Co alloy, an Fe—Ni alloy, anFe—Al alloy, or an Fe—Si alloy is most preferably used. On the otherhand, in order to enhance a shield effect on a higher frequency side (50to several hundreds of MHz), a ferrite film formed of NiZn, MnZn, orNiCuZn, or Fe is most preferably used.

When a foil or a bulk sheet is used as the magnetic film 50, the foil orbulk sheet may be previously processed into a size corresponding to theplanar size of the concave portion 47 and then adhered to the concaveportion 47 of the mold resin 40.

The top surface 51 of the magnetic film 50, the top and side surfaces 41and 42 of the mold resin 40 and the side surface 27 of the substrate 20are covered with the metal film 60. The metal film 60 serves as anelectromagnetic shielding and is preferably mainly composed of at leastone metal selected from a group consisting of Au, Ag, Cu, and Al. Themetal film 60 preferably has a resistance as low as possible and mostpreferably uses Cu in terms of cost. An outer surface of the metal film60 is preferably covered with an anticorrosive metal such as SUS, Ni,Cr, Ti, or brass or an antioxidant film made of a resin such as an epoxyresin, a phenol resin, an imide resin, an urethane resin, or a siliconeresin. The reason for this is that the metal film 60 undergoes oxidativedeterioration by an external environment such as heat or humidity; and,therefore, the aforementioned treatment is preferable to suppress andprevent the oxidative deterioration. A formation method for the metalfilm 60 may be appropriately selected from known methods, such as asputtering method, a vapor-deposition method, an electroless platingmethod, an electrolytic plating method. Before formation of the metalfilm 60, pretreatment for enhancing adhesion, such as plasma treatment,coupling treatment, blast treatment, or etching treatment, may beperformed. As a base of the metal film 60, a high adhesion metal filmsuch as a titanium film, a chromium film, or an SUS film may be formedthinly in advance.

As illustrated in FIG. 1, the power supply patterns 25G are exposed tothe side surfaces 27 of the substrate 20. The metal film 60 covers theside surfaces 27 of the substrate 20 and is thereby electricallyconnected to the power supply pattern 25G. The metal film 60 may contactto the power supply pattern 25G formed on the front surface 21 of thesubstrate 20.

Although not especially limited, it is desirable that a resistance valueat an interface between the metal film 60 and the magnetic film 50 isequal to or larger than 10⁶Ω. According to this configuration, an eddycurrent generated when electromagnetic wave noise enters the metal film60 hardly flows in the magnetic film 50, which can prevent deteriorationin the magnetic characteristics of the magnetic film 50 due to inflow ofthe eddy current. The resistance value at the interface between themetal film 60 and the magnetic film 50 refers to a surface resistance ofthe magnetic film 50 when the metal film 60 and magnetic film 50directly contact each other and to a surface resistance of an insulatingfilm when the insulating film is present between the metal film 60 andthe magnetic film 50.

In order to make a resistance value at an interface between the metalfilm 60 and the magnetic film 50 equal to or higher than 10⁶Ω, amaterial having a sufficiently high surface resistance is used as thematerial for the magnetic film 50 or a thin insulating material isformed on the top surface 51 of the magnetic film 50.

As described above, in the electronic circuit package 11A according tothe present embodiment, the region above the electronic component 31 forwhich noise countermeasures are particularly required is covered with alaminated film of the magnetic film 50 and metal film 60, enabling acomposite shield structure for the electronic component 31 to beobtained. Particularly, in the present embodiment, the magnetic film 50and the metal film 60 are laminated in this order, so thatelectromagnetic wave noise radiated from the electronic component 31 isshielded more effectively than in the case where the lamination orderthereof is reversed. This is because the electromagnetic wave noiseradiated from the electronic component 31 is partially absorbed whenpassing through the magnetic film 50, and part of the electromagneticwave noise that has not been absorbed by the magnetic film 50 isreflected by the metal film 60 and passes again through the magneticfilm 50. As described above, the magnetic film 50 acts twice on theelectromagnetic wave noise incident thereon, thereby making it possibleto effectively shield the electromagnetic wave noise radiated from theelectronic component 31.

Further, in the present embodiment, the magnetic film 50 is buried inthe concave portion 47, so that an increase in the height of the entireelectronic circuit package 11A due to addition of the magnetic film 50can be eliminated, whereby a demand for height reduction can besatisfied.

Further, the magnetic film 50 is formed directly on the upper surface 41of the mold resin 40, that is, an adhesive or the like is not interposedbetween the magnetic film 50 and the mold resin 40, which isadvantageous for height reduction of a product. In addition, in thepresent embodiment, the magnetic film 50 is formed only in the concaveportion 47 of the mold resin 40, enabling the metal film 60 to be easilyconnected to the power supply pattern 25G.

The following describes a manufacturing method for the electroniccircuit package 11A according to the present embodiment.

FIGS. 2 to 5 are process views for explaining a manufacturing method forthe electronic circuit package 11A.

As illustrated in FIG. 2, an assembly substrate 20A having a multilayerwiring structure is prepared. A plurality of the land patterns 23 areformed on the front surface 21 of the assembly substrate 20A, and aplurality of the external terminals 26 are formed on the back surface 22of the assembly substrate 20A. Further, a plurality of the internalwirings 25 including the power supply patterns 25G are formed in aninner layer of the assembly substrate 20A. A dashed line a in FIG. 2denotes apart to be cut in a subsequent dicing process. As illustratedin FIG. 2, the power supply patterns 25G are provided at a positionoverlapping the dashed line a in a plan view.

Then, as illustrated in FIG. 2, the plurality of electronic components31 and 32 are mounted on the front surface 21 of the assembly substrate20A so as to be connected to the land patterns 23. Specifically, thesolder 24 is provided on the land pattern 23, followed by mounting ofthe electronic components 31 and 32 and by reflowing, whereby theelectronic components 31 and 32 are connected to the land patterns 23.

Then, as illustrated in FIG. 3, the mold resin 40 is used to cover thesurface 21 of the assembly substrate 20A so as to embed the electroniccomponents 31 and 32 therein. As a formation method for the mold resin40, a compression method, an injection method, a print method, adispense method, a nozzle coating method, or the like can be used. Themold resin 40 is formed so as to form the concave portion 47 above thefirst region 21A, that is, at a part thereof that covers the electroniccomponent 31.

As a method for forming the concave portion 47 in the mold resin 40,there can be adopted a method as illustrated in FIG. 6. That is, aconvex portion 83 corresponding to the concave portion 47 is formed inone of two dies 81 and 82 for pressing a molding material 40 a. In thisexample, the convex portion 83 is formed in the die 81 positioned on theupper surface 41 side of the mold resin 40. According to this method, itis possible to form the concave portion 47 in the mold resin 40 withoutincreasing the number of processes.

Alternatively, dies 81 and 82 that do not have the convex portion 83 areused to press the molding material 40 a as illustrated in FIG. 7, andthen blasting is performed through a mask 84 having an openingcorresponding to the first region 21A as illustrated in FIG. 8. Furtheralternatively, a metal film 85 is formed on the flat upper surface 41 ofthe mold resin 40 as illustrated in FIG. 9, then the metal film 85corresponding to the first region 21A is removed by patterning asillustrated in FIG. 10, and then blasting is performed through thepatterned metal film 85 as illustrated in FIG. 11.

After the mold resin 40 having the concave portion 47 is thus formed,the magnetic film 50 is formed in the concave portion 47 of the moldresin 40 as illustrated in FIG. 4. In order to enhance adhesion betweenthe mold resin 40 and the magnetic film 50, the bottom surface of theconcave portion 47 may be subjected to blasting or etching to form aphysical irregularity thereon, may be subjected to surface modificationby means of plasma or short wavelength UV, or may be subjected toorganofunctional coupling treatment.

When the film formed of a composite magnetic material is used as themagnetic film 50, a thick-film formation method such as a printingmethod, a molding method, a slit nozzle coating method, a spray method,a dispensing method, an injection method, a transfer method, acompression molding method, or a lamination method using an uncuredsheet-like resin can be used. When the magnetic film 50 is formed byusing the printing method, slit nozzle method, spraying method, ordispensing method, the viscosity of the composite magnetic material ispreferably controlled as needed. The viscosity control may be made bydiluting the composite magnetic material with one or two or moresolvents having a boiling point of 50° C. to 300° C. The thermosettingmaterial mainly consists of a main agent, a curing agent, and a curingaccelerator; however, two or more kinds of main agent or curing agentmay be blended according to required characteristics. Further, two ormore kinds of solvents may be mixed: a coupling agent for enhancingadhesion and fluidity, a fire retardant for flame retardancy, a dye anda pigment for coloration, a non-reactive resin material for impartingflexibility, and a non-magnetic filler for adjusting a thermal expansioncoefficient may be blended. The materials may be kneaded or dispersed bya known means such as a kneader, a mixer, a vacuum defoaming stirringmachine, or a three-roll mill.

Further, when a thin film formed of a soft magnetic material or ferriteis used as the magnetic film 50, a plating method, a spraying method, anSD method, or a thermal spraying method may be used as well as a thinfilm formation method such as a sputtering method or vapor depositionmethod. When a thin film formed of a foil or a bulk sheet is used as themagnetic film 50, the foil or bulk may previously be cut according tothe planar size of the concave portion 47 and then adhered to theconcave portion 47 by an adhesive or the like.

Then, as illustrated in FIG. 5, the assembly substrate 20A is cut alongthe dashed line a to divide the assembly substrate 20A into individualsubstrates 20. In the present embodiment, the power supply patterns 25Gpass the dashed line a as a dicing position. Thus, when the assemblysubstrate 20A is cut along the dashed line a, the power supply patterns25G are exposed from the side surface 27 of the substrate 20.

Then, the metal film 60 is formed so as to cover the top surface 51 ofthe magnetic film 50, the top and side surfaces 41 and 42 of the moldresin 40, and side surface 27 of the substrate 20, whereby theelectronic circuit package 11A according to the present embodiment iscompleted. Examples of a formation method for the metal film 60 mayinclude a sputtering method, a vapor-deposition method, an electrolessplating method, and an electrolytic plating method. Before formation ofthe metal film 60, pretreatment for enhancing adhesion, such as plasmatreatment, coupling treatment, blast treatment, or etching treatment,may be performed. As a base of the metal film 60, a high adhesion metalfilm such as a titanium film or a chromium film may be formed thinly inadvance.

As described above, according to the manufacturing method for theelectronic circuit package 11A of the present embodiment, the concaveportion 47 is formed simultaneously with or after formation of the moldresin 40, and the magnetic film 50 is buried in the concave portion 47,so that it is possible to cover the region above the electroniccomponent 31 with the laminated film of the magnetic film 50 and metalfilm 60 without increasing the height of the entire electronic circuitpackage 11A. Further, the assembly substrate 20A is cut off to exposethe power supply pattern 25G therethrough, which makes it possible toeasily and reliably connect the metal film 60 to the power supplypattern 25G.

FIG. 12 is a cross-sectional view illustrating a configuration of anelectronic circuit package 11B according to a first modification of thefirst embodiment.

As illustrated in FIG. 12, the electronic circuit package 11B accordingto the first modification differs from the electronic circuit package11A illustrated in FIG. 1 in that the upper surface of the electroniccomponent 31 is exposed to the concave portion 47 with the result thatthe magnetic film 50 is brought into contact with the upper surface ofthe electronic component 31. Other configurations are the same as thoseof the electronic circuit package 11A illustrated in FIG. 1. Thus, thesame reference numerals are given to the same elements, and overlappingdescription will be omitted.

According to the configuration illustrated in FIG. 12, the filmthickness of the magnetic film 50 can be made larger, whereby magneticshielding characteristics can be enhanced. Further, when a materialhaving a thermal conductivity higher than that of the mold resin 40 isused as a material for the magnetic film 50, heat radiation performancefor the electronic component 31 can be enhanced. To obtain the structureillustrated in FIG. 12, blasting may be performed in, e.g., a blastingprocess for formation of the concave portion 47 until the upper surfaceof the electronic component is exposed. Alternatively, the magnetic film50 is previously adhered onto the upper surface of the electroniccomponent 31 in a formation process of the mold resin 40 using the dies81 and 82, followed by molding, whereby the structure illustrated inFIG. 12 can be obtained.

FIG. 13 is a cross-sectional view illustrating a configuration of anelectronic circuit package 11C according to a second modification of thefirst embodiment.

As illustrated in FIG. 13, the electronic circuit package 11C accordingto the second modification differs from the electronic circuit package11A illustrated in FIG. 1 in that a side magnetic film 53 as a part ofthe magnetic film 50 covers a part of a side surface 42 of the moldresin 40. Other configurations are the same as those of the electroniccircuit package 11A illustrated in FIG. 1. Thus, the same referencenumerals are given to the same elements, and overlapping descriptionwill be omitted.

According to the configuration illustrated in FIG. 13, noise radiatedfrom the electronic component 31 toward the side direction and noise tobe incident on the electronic component 31 from the side direction canbe attenuated. In this case, the side magnetic film 53 may have a lengthequal to (see FIG. 14) or longer than (see FIG. 15) the concave portion47 in a plan view. Further, when the electronic component 31 is disposednear a corner portion of the substrate 20, the side magnetic film 53 maybe provided along two sides of the concave portion 47 in a plan view(see FIG. 16). Further, in this case, the lengths of the two sides ofthe side magnetic film 53 may be extended in a plan view (see FIG. 17).In any cases, the side magnetic film 53 can be formed by forming anotherconcave portion in the region where the side magnetic film 53 is to beformed in a forming process of the concave portion 47 in the mold resin40 and burying a magnetic material in the another concave portion.

Second Embodiment

FIG. 18 is a cross-sectional view illustrating a configuration of anelectronic circuit package 12A according to a second embodiment.

As illustrated in FIG. 18, the electronic circuit package 12A accordingto the present embodiment differs from the electronic circuit package11A illustrated in FIG. 1 in that the lamination order of the magneticfilm 50 and the metal film 60 in the concave portion 47 is reversed.That is, in the concave portion 47, the metal film 60 is positionedbetween the mold resin 40 and the magnetic film 50. Other configurationsare the same as those of the electronic circuit package 11A illustratedin FIG. 1. Thus, the same reference numerals are given to the sameelements, and overlapping description will be omitted.

In the present embodiment as well, the region above the electroniccomponent 31 for which noise countermeasures are especially required iscovered with the laminated film of the metal film 60 and magnetic film50, enabling a composite shield structure for the electronic component31 to be obtained. Particularly, in the present embodiment, the metalfilm 60 and magnetic film 50 are laminated in this order, so thatelectromagnetic wave noise to be incident on the electronic component 31is shielded more effectively. This is because external electromagneticwave noise is partially absorbed by the magnetic film 50 when passingtherethrough, and part of the electromagnetic wave noise that has notbeen absorbed by the magnetic film 50 is reflected by the metal film 60and passes again through the magnetic film 50. As described above, themagnetic film 50 acts twice on the external electromagnetic wave noise,which makes it possible to effectively shield the externalelectromagnetic wave noise to be incident on the electronic component31.

The following describes a manufacturing method for the electroniccircuit package 12A according to the present embodiment.

First, the mold resin 40 having the concave portion 47 is formed on thesurface 21 of the assembly substrate 20A according to the methoddescribed using FIGS. 2 and 3. Then, as illustrated in FIG. 19, theassembly substrate 20A is cut off along the dashed line a (see FIG. 2)to individuate the substrate 20. As a result, the power supply pattern25G is exposed to a side surface 27 of the substrate 20.

Then, as illustrated in FIG. 20, the metal film 60 is formed so as tocover the upper surface 41 and side surface 42 of the mold resin 40including the concave portion 47 and the side surface 27 of thesubstrate 20. As a result, the metal film 60 is connected to the powersupply pattern 25G exposed to the side surface 27 of the substrate 20.Further, the concave portion 47 is covered with the metal film 60. Atthis time, the depth of the concave portion 47 and the thickness of themetal film 60 need to be set so that the concave portion 47 is notcompletely filled with the metal film 60.

Finally, the magnetic film 50 is buried in the concave portion 47 of themold resin 40, whereby the electronic circuit package 12A according tothe present embodiment is completed. In this manufacturing method, themetal film 60 is formed before formation of the magnetic film 50, sothat the metal film 60 and magnetic film 50 can be laminated in thisorder.

FIG. 21 is a cross-sectional view illustrating a configuration of anelectronic circuit package 12B according to a first modification of thesecond embodiment.

As illustrated in FIG. 21, the electronic circuit package 12B accordingto the first modification differs from the electronic circuit package12A illustrated in FIG. 18 in that the upper surface of the electroniccomponent 31 is exposed to the concave portion 47 with the result thatthe metal film 60 is brought into contact with the upper surface of theelectronic component 31. Other configurations are the same as those ofthe electronic circuit package 12A illustrated in FIG. 18. Thus, thesame reference numerals are given to the same elements, and overlappingdescription will be omitted.

According to the configuration illustrated in FIG. 21, the thickness ofthe magnetic film 50 can be made larger, so that magnetic shieldingcharacteristics can be enhanced. In addition, the upper surface of theelectronic component 31 contacts the metal film 60 having a high thermalconductivity, so that high heat radiation efficiency can be obtained.

FIG. 22 is a cross-sectional view illustrating a configuration of anelectronic circuit package 12C according to a second modification of thesecond embodiment.

As illustrated in FIG. 22, the electronic circuit package 12C accordingto the second modification differs from the electronic circuit package12A illustrated in FIG. 18 in that the side magnetic film 53 as a partof the magnetic film 50 covers a part of the side surface 42 of the moldresin 40. Other configurations are the same as those of the electroniccircuit package 12A illustrated in FIG. 18. Thus, the same referencenumerals are given to the same elements, and overlapping descriptionwill be omitted.

According to the configuration illustrated in FIG. 22, noise radiatedfrom the electronic component 31 toward the side direction and noise tobe incident on the electronic component 31 from the side direction canbe attenuated. In this case also, the side magnetic film 53 may have alength equal to (see FIG. 14) or longer than (see FIG. 15) the concaveportion 47 in a plan view. Further, when the electronic component 31 isdisposed near a corner portion of the substrate 20, the side magneticfilm 53 may be provided along two sides of the concave portion 47 in aplan view (see FIG. 16). Further, in this case, the lengths of the twosides of the side magnetic film 53 may be extended in a plan view (seeFIG. 17).

Third Embodiment

FIG. 23 is a cross-sectional view illustrating a configuration of anelectronic circuit package 13A according to a third embodiment of thepresent invention.

As illustrated in FIG. 23, the electronic circuit package 13A accordingto the present embodiment differs from the electronic circuit package12A illustrated in FIG. 18 in that the upper surface of the magneticfilm 50 is covered with a metal film 63 different from the metal film60. Other configurations are the same as those of the electronic circuitpackage 12A illustrated in FIG. 18. Hence, the same reference numeralsare given to the same elements, and overlapping description will beomitted.

In the present embodiment, the region above the electronic component 31for which noise countermeasures are particularly required is coveredwith a three-layer laminated film of the metal film 60 (first metalfilm), magnetic film 50, and metal film 63 (second metal film). Thus,electromagnetic wave noise radiated from the electronic component 31 canbe shielded effectively as in the first embodiment, and externalelectromagnetic wave noise to be incident on the electronic component 31can be shielded effectively as in the second embodiment. This makes itpossible to obtain very high shielding effect while achieving heightreduction.

The following describes a manufacturing method for the electroniccircuit package 13A according to the present embodiment.

First, the mold resin 40 having the concave portion 47 is formed on thesurface 21 of the assembly substrate 20A according to the methoddescribed using FIGS. 2 and 3. Then, as illustrated in FIG. 24, themetal film 60 is formed so as to cover the upper surface 41 of the moldresin 40 including the concave portion 47. As a result, the metal film60 is formed on the bottom of the concave portion 47. At this time, thedepth of the concave portion 47 and the thickness of the metal film 60need to be set so that the concave portion 47 is not completely filledwith the metal film 60.

Then, as illustrated in FIG. 25, the concave portion 47 of the moldresin 40 is filled with the magnetic film 50 and then, as illustrated inFIG. 26, the assembly substrate 20A is cut off along the dashed line a(see FIG. 2) to individuate the substrate 20. As a result, the powersupply pattern 25G is exposed to the side surface 27 of the substrate20.

Finally, the metal film 63 is formed so as to cover the upper surface 41and side surface 42 of the mold resin 40 and side surface 27 of thesubstrate 20, whereby the electronic circuit package 13A according tothe present embodiment is completed. In this manufacturing method, themetal films 60 and 63 are formed before and after formation of themagnetic film 50, so that the three-layer laminated film of the firstmetal film 60, magnetic film 50, and second metal film 63 can beobtained.

FIG. 27 is a cross-sectional view illustrating a configuration of anelectronic circuit package 13B according to a first modification of thethird embodiment.

As illustrated in FIG. 27, the electronic circuit package 13B accordingto the first modification differs from the electronic circuit package13A illustrated in FIG. 23 in that the upper surface of the electroniccomponent 31 is exposed to the concave portion 47, allowing the metalfilm 60 to contact with the upper surface of the electronic component31. Other configurations are the same as those of the electronic circuitpackage 13A illustrated in FIG. 23. Thus, the same reference numeralsare given to the same elements, and overlapping description will beomitted.

According to the configuration illustrated in FIG. 27, the filmthickness of the magnetic film 50 can be made larger, whereby magneticshielding characteristics can be enhanced. In addition, the uppersurface of the electronic component contacts the metal film 60 having ahigh thermal conductivity, so that high heat radiation efficiency can beobtained.

FIG. 28 is a cross-sectional view illustrating a configuration of anelectronic circuit package 13C according to a second modification of thethird embodiment.

As illustrated in FIG. 28, the electronic circuit package 13C accordingto the second modification differs from the electronic circuit package13A illustrated in FIG. 23 in that the side magnetic film 53 as a partof the magnetic film 50 covers a part of the side surface 42 of the moldresin 40. Other configurations are the same as those of the electroniccircuit package 13A illustrated in FIG. 23. Thus, the same referencenumerals are given to the same elements, and overlapping descriptionwill be omitted.

According to the configuration illustrated in FIG. 28, noise radiatedfrom the electronic component 31 toward the side direction and noise tobe incident on the electronic component 31 from the side direction canbe attenuated. In this case also, the side magnetic film 53 may have alength equal to (see FIG. 14) or longer than (see FIG. 15) the concaveportion 47 in a plan view. Further, when the electronic component 31 isdisposed near a corner portion of the substrate 20, the side magneticfilm 53 may be provided along two sides of the concave portion 47 in aplan view (see FIG. 16). Further, in this case, the lengths of the twosides of the side magnetic film 53 may be extended in a plan view (seeFIG. 17).

While the preferred embodiments of the present invention have beendescribed, the present invention is not limited thereto. Thus, variousmodifications may be made without departing from the gist of theinvention, and all of the modifications thereof are included in thescope of the present invention.

Examples

<Production of Composite Magnetic Paste>

A composite magnetic paste was produced in the following way.

First, as an Fe-based spherical magnetic filler, AKT 4.5Si-5.0Cr (D50=30μm) manufactured by Mitsubishi Steel Mfg. Co., Ltd. and carbonyl ironpowder (D50=6 μm) manufactured by BASF Corporation were prepared. Then,AKT 4.5Si-5.0Cr and carbonyl iron powder were added to a thermosettingresin in a ratio of 8:2 at 90 wt. % in total. As for the thermosettingresin used, 830S (bisphenol A epoxy resin) made by Dainippon Ink &Chemicals, Inc. was used as a base resin, 0.5 equivalent of DicyDD (DigiAngi amide) made by Nippon Carbide Industries Co., Inc. was added to thebase resin as a curing agent, and 1 wt. % of C11Z-CN (imidazole) made byShikoku Chemicals Corporation was added to the base resin as a curingaccelerator. Then, the above resin materials were blended together,followed by kneading and stirring by a vacuum defoaming stirringmachine. After that, butylcarbitol acetate was added at appropriatetiming so that the viscosity at 10 rpm is 50 Pa·S, followed by kneadingand stirring again by the vacuum defoaming stirring machine, whereby acomposite magnetic material paste was obtained.

<Physical Property Evaluation of Magnetic Film Sheet>

Then, a substrate for shield evaluation having a 50Ω, resistor mountedthereon was prepared and was seal-molded by compression molding withG-770H manufactured by Sumitomo Bakelite Co., Ltd. used as a moldingmaterial. Thereafter, according to the method described in FIGS. 9 to11, a concave portion having a 100 μm depth was formed in a 3 mm×3 mmarea including a portion where the 50Ω resistor is mounted in a planview. As a blasting process, wet blasting was performed.

Then, the above composite magnetic material paste was injected into theconcave portion and then heat-cured at 180° C. for 60 minutes.Thereafter, a dicer was used to individuate the substrate to expose aground pattern to the side surface of the substrate. Then, electrolessplating was performed to form a metal film composed of a laminated filmof Cu (film thickness of 1 μm) and Ni (film thickness of 2 μm) on theupper surface of the magnetic film, the upper surface and side surfaceof the mold resin, and the side surface of the substrate so as tocontact the ground pattern, whereby a noise attenuation measurementsample A (working example) was obtained.

On the other hand, a noise attenuation measurement sample B (comparativeexample) was produced by a method similar to the production method forthe noise attenuation measurement sample A; however, the magnetic filmand metal film were not formed.

The noise attenuation measurement samples A and B were each connected toa signal generator, and a signal of an arbitrary frequency wastransmitted to the 50Ω, resistor, whereby the amount of noise radiatedfrom each sample was measured by a neighboring magnetic field measuringapparatus. As a result, as compared to the noise attenuation measurementsample B, the noise attenuation measurement sample A exhibitedattenuation effect of about 55 dBμV at 100 MHz and about 48 dBμV at 1.2GHz. Further, in the noise attenuation measurement sample B, awell-defined peak was found around the 50Ω resistor as a noisegeneration source; on the other hand, in the noise attenuationmeasurement sample A, there was no peak, and noise was attenuated tosubstantially the same level over the entire surface. This indicatesthat not by applying the magnetic shield to the entire package, but byselectively applying it to the noise generation source, the peak noiseis eliminated to thereby provide sufficient shielding effect. Thus,effectiveness of the present invention was confirmed.

What is claimed is:
 1. An electronic circuit package comprising: asubstrate having a main surface, the main surface having a first regionand a second region located on a same plane as the first region; a firstelectronic component mounted on the first region; a second electroniccomponent mounted on the second region; a mold resin that covers themain surface of the substrate so as to embed the first and secondelectronic components therein; a magnetic film formed on the mold resin;and a metal film formed on the mold resin, wherein the metal film coversthe first electronic component with an intervention of the magnetic filmwhile the metal film covers the second electronic component without anintervention of the magnetic film.
 2. The electronic circuit package asclaimed in claim 1, wherein the first electronic component is lower inheight than the second electronic component.
 3. The electronic circuitpackage as claimed in claim 1, wherein the mold resin has a firstthickness on the first region and a second thickness greater than thefirst thickness on the second region.
 4. The electronic circuit packageas claimed in claim 1, wherein the mold resin has a first side surfaceadjacent to the first electronic component and a second side surfaceadjacent to the second electronic component, wherein the first sidesurface is covered with the magnetic film, and wherein the second sidesurface is free from the magnetic film.
 5. An electronic circuit packagecomprising: a substrate having a power supply pattern; a firstelectronic component mounted on a first region of a front surface of thesubstrate; a mold resin that covers the front surface of the substrateso as to embed the first electronic component therein and has a concaveportion above the first region; a magnetic film selectively provided inthe concave portion; and a first metal film that is connected to thepower supply pattern and covers the mold resin, wherein the first metalfilm is positioned between the mold resin and the magnetic film in theconcave portion.
 6. The electronic circuit package as claimed in claim5, further comprising a second metal film that covers the magnetic film.7. An electronic circuit package comprising: a substrate having a powersupply pattern; a first electronic component mounted on a first regionof a front surface of the substrate; a mold resin that covers the frontsurface of the substrate so as to embed the first electronic componenttherein and has a concave portion above the first region; a magneticfilm selectively provided in the concave portion; and a first metal filmthat is connected to the power supply pattern and covers the mold resin,wherein an upper surface of the first electronic component is exposed tothe concave portion, thereby the upper surface of the first electroniccomponent contacts the magnetic film or the first metal film.
 8. Anelectronic circuit package comprising: a substrate having a mainsurface, the main surface having a first region and a second region; afirst electronic component mounted on the first region; a secondelectronic component mounted on the second region; a mold resin thatcovers the main surface of the substrate so as to embed the first andsecond electronic components therein; a magnetic film formed on the moldresin; and a metal film formed on the mold resin, wherein the metal filmcovers the first electronic component with an intervention of themagnetic film while the metal film covers the second electroniccomponent without an intervention of the magnetic film, wherein themetal film covers the first electronic component without an interventionof the mold resin.